Internal Arc LZMA vs external LZMA2
 

Hello,
Should i consider switching to external lzma2 instead of internal lzma for better compression ratio?
What do you suggest to get the best ratio out of lzma?

LZMA2 usually have worster compression ratio than LZMA1, but can be faster due to saving of uncompressible blocks as is.

You can better the compression ratio with LZMA 1 by increasing the RAM usage. That is like "d512" parameter. Increase the value of "d" ( that memory is needed to decompress) & you will get better ratio, of course other parameters must be set correctly. Decompression will be faster also but will use more RAM.

I'm using these parameters and i can't seems to get a better compression ratio out of it no matter what i adjust
"lzma:a1:mfbt4:d180m:fb273:mc10000:lc8"
what's the better version of these parameters would be as you suggest?

imho its the best.
increase d180m to d1024m if you have enought RAM.

you need to use fazip 64x for lzma beyond d184mb because lzma built-in freearc is limited..

[External compressor:mm,dispack070,rep,tor,delta,4x4,lzma]
header = 0
packcmd = fazip -i0 compress:{compressor}{:option} <stdin> <stdout>

First at all internal arc LZMA is 32bit so you have a memory limitation thats why lzma_x64 was created you can use 4gb of memory the same thing with srep x64. external x64 always is better than internal x86.(fazip_x64 is the best !!!!)
LZMA and LZMA2 are different.
LZMA Better for compression ratio.
LZMA2 Better for time decompression .

ChronoCross:

Then how would the parameters for fazip and srep X64 to use 4gb decompression

I think you confused, 4gb in decompression is a requirement and not an optimization.
The optimization would be to limit the memory to decompress.
This would be during the compression in freearc "-ld512".
You can use 4gb for compress and then 512mb to decompress.

can someone give fazip x64 i haven't found it in freearc's site is broken and is there x64 arc.exe ?

Here's Fazipx64. :)

I used this parameter and it works.
lzma:a1:mfbt4:d180m:fb273:mc10000:lc8

But change d180m by :d256m and it takes longer to compress, but compresses a little more.

My question is, how do I use my cpu 100% because in the image it is only seen that it uses 50% when compressing

http://i.imgur.com/Bp6Udt6g.png

[External compressor:rep,mm,delta,exe,exe2,4x4,lzma]
header = 0
packcmd = FAZip64 -i0 compress:{compressor}{:option} <stdin> <stdout>
unpackcmd = FAZip64 -i0 decompress:{compressor}{:option} <stdin> <stdout>

4x4:lzma: a1: mfbt4: d180m: fb273: mc10000: lc8
But the more RAM